The three component Projects in this application are each devoted to one or more aspects of the functional bioenergetic consequences of changes in mitochondrial composition or environment in age-related animal disease models, whether in isolated nerve terminals (projects 1 and 3) cell lines (projects 1 and 2) or primary neuronal cultures (project 1). The broad objectiveof the Bioenergetics Core is to provide a common platform across each Project for the design, execution and analysis of die subset of experiments that involve an analysis of mitochondrial function. The projects are focused around mitochondrial respiratory chain complexes (project 1), the mutual interactions of the glutathione thiol redox control pathways and the mitochondrion (projects 1,2),the consequences of defective scavenging of superoxide generated by the respiratory chain (projects 2, 3) and the interactions of p53 with the mitochondrion (project 2). The specific aims of the Bioenergetics Coreare: 1. To provide an intellectual and practical resource to assist Project Leaders in the design and analysisof specific experiments whose purpose is to investigate mitochondrial bioenergetic function in the variety of age-related disease models studied in the program. 2. To provide detailed and comprehensive assistance to the projects in the planning, execution and interpretation of assays of mitochondrial function in a variety of models including cell lines, fibroblasts, primary neurons and isolated nerve terminals. Assays will include respiration of cells, synaptosomes and isolated mitochondria, proton leak quantification,respiratory capacity, ATP turnover, mitochondrial and plasma membrane potentials, mitochondrial and cytoplasmic reactive oxygen species, ATP/ ADP ratios, NAD(P)H and glutathione levels, redox status, and cytoplasmicand matrix free Ca2+. 3. To utilize isolated mitochondria from brain and other tissues as models to test and generate hypotheses concerning the quantitative consequences for the mitochondrial bioenergetic network of subtle modulations in respiratory capacity, membrane potential, proton leak, glutathione pool size, pro-apoptotic stimulietc. 4. To aid the integration of the results obtained in the bioenergetic studies from the three Projects along with structural data from Proteomics Core C into a coherent picture of mitochondrial stress, aging and age- related disease.